Image Compressor
Compress any image to a size you choose. Set a target in kilobytes and the tool finds the highest quality that fits under it.
Leave blank for best quality with no size limit.
Finding the best quality that fits…
- Original
- —
- Result
- —
- Reduction
- —
- Dimensions
- —
How to use this tool
- Select your file, drag it onto the box above, or paste it from your clipboard.
- Processing starts automatically — there is nothing to configure.
- Check the result panel, which shows the original size, the final size and the output dimensions.
- Click Download to save it.
This is the general-purpose version. If you need a specific figure that a form demands — 20 KB, 50 KB, 100 KB — the preset pages skip the setup and go straight to that target.
The specification
| Target size | Whatever you enter, in KB |
|---|---|
| Output format | JPEG |
| Method | Binary search over JPEG quality |
| Input formats | JPG, PNG, WebP, GIF, BMP |
| Maximum input | 25 MB |
Why uploads get rejected
Meeting the size is only part of it. These are the failures that actually come up:
- The image is a PNG screenshot and the target is very small. PNG photos are far larger than the JPEG equivalent — converting is usually enough on its own.
- The source is enormous in pixel terms. The tool shrinks dimensions automatically when quality alone cannot reach the target.
- The file has already been compressed several times, so quality degrades quickly.
How it works
Most compressors pick a fixed quality level and hope for the best, which is why they either overshoot the limit or land far below it and throw away detail you did not need to lose.
This tool runs a binary search instead. It encodes your image at a mid-range quality, measures the resulting file, then narrows the range — higher if there is room, lower if it is over — repeating seven times. It keeps the largest result that still fits. If the lowest quality is still too big, it reduces the pixel dimensions and searches again.
All of it runs on your own device using the browser's canvas API. Nothing is transmitted.
Who uses this
Anyone who needs a smaller image without a specific published requirement — email attachments, faster web pages, or fitting under an upload cap you can see on screen.
Frequently asked questions
What target should I choose?
For web images, 100–300 KB is a good balance. For a form with a stated limit, use that figure. For an email attachment, anything under 1 MB is comfortable.
Why is the output always JPEG?
JPEG reaches small file sizes on photographs far more efficiently than PNG, and it is the format upload forms accept most reliably. If you need PNG or WebP specifically, use the dedicated converter pages.
Will the quality drop?
Some quality is always lost when a file gets smaller — that is what compression means. The tool searches for the highest quality that still fits under your limit, so it gives up as little as possible.
Are my files uploaded to a server?
No. Everything runs inside your browser on your own device. Your file is never transmitted and never stored by us. You can confirm this by opening your browser’s Network tab while you use the tool — you will see no upload request.
Is there a limit on how many files I can process?
No. There is no daily cap, no account, and no watermark. Because the work happens on your device rather than our servers, there is nothing for us to ration.
Is this tool really free?
Yes — no account, no trial, no watermark, and no cap on usage. It runs on your own device rather than our servers, so there is no cost for us to pass on.
Does it work on mobile?
Yes. The interface adapts to phone and tablet screens, and everything runs in the browser, so there is no app to install.
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Your files stay on your device. This tool runs entirely in your browser. No file is uploaded, transmitted, or stored. You can verify this by opening your browser's Network tab while using the tool.
Disclaimer. Specifications published by exam boards, governments and platforms change without notice. We verify and date every specification on this site, but you should always confirm against the official source before submitting an application. See our full disclaimer.